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authorTheodore Ts'o <tytso@mit.edu>2013-03-11 23:39:59 -0400
committerTheodore Ts'o <tytso@mit.edu>2013-03-11 23:39:59 -0400
commit90ba983f6889e65a3b506b30dc606aa9d1d46cd2 (patch)
tree964ad0ccf415e73a7760b5bfe65506f5d825e1cf /fs/ext4/ialloc.c
parentad56edad089b56300fd13bb9eeb7d0424d978239 (diff)
downloadlinux-90ba983f6889e65a3b506b30dc606aa9d1d46cd2.tar.bz2
ext4: use atomic64_t for the per-flexbg free_clusters count
A user who was using a 8TB+ file system and with a very large flexbg size (> 65536) could cause the atomic_t used in the struct flex_groups to overflow. This was detected by PaX security patchset: http://forums.grsecurity.net/viewtopic.php?f=3&t=3289&p=12551#p12551 This bug was introduced in commit 9f24e4208f7e, so it's been around since 2.6.30. :-( Fix this by using an atomic64_t for struct orlav_stats's free_clusters. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Lukas Czerner <lczerner@redhat.com> Cc: stable@vger.kernel.org
Diffstat (limited to 'fs/ext4/ialloc.c')
-rw-r--r--fs/ext4/ialloc.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 32fd2b9075dd..6c5bb8d993fe 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -324,8 +324,8 @@ error_return:
}
struct orlov_stats {
+ __u64 free_clusters;
__u32 free_inodes;
- __u32 free_clusters;
__u32 used_dirs;
};
@@ -342,7 +342,7 @@ static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
if (flex_size > 1) {
stats->free_inodes = atomic_read(&flex_group[g].free_inodes);
- stats->free_clusters = atomic_read(&flex_group[g].free_clusters);
+ stats->free_clusters = atomic64_read(&flex_group[g].free_clusters);
stats->used_dirs = atomic_read(&flex_group[g].used_dirs);
return;
}